Speculation is growing that the wife of Huddersfield suicide bomber Jermaine Lindsay is involved in the Kenyan shopping mall terrorist attack.

The Foreign Office is investigating suggestions that Samantha Lewthwaite, nicknamed the “White Widow”, could have been linked to the plot.

Witness accounts have suggested a woman was among the attackers, fuelling speculation that Lewthwaite, who is already being hunted by police, could be one of the terrorists involved in the attack by Islamic extremists in the upmarket shopping centre which has left 68 dead and more than 170 injured, including many children.

Ms Lewthwaite converted to Islam at the age of 15 and married Lindsay in 2002.

A Foreign Office spokesman said: “We are aware of the reports and we are looking into them.”

The spokesman added: “It is really difficult to substantiate. We are looking at the names and seeing what we can find out.”

A Twitter account purporting to be an al-Shabaab spokesman named a 24-year-old man from London as one of the gunmen.

The @hsm_press2 account listed a string of names it claimed were involved in the attack before being closed down, as previous usernames linked to the terrorist group had been.

Jermaine Lindsay

The Kenya Defence Forces said they are now in control of the majority of the shopping mall.

“Most of the hostages have been rescued and security forces have taken control of most parts of the building ... all efforts are underway to bring this matter to a speedy conclusion,” it said on Twitter.

Gunfire has reportedly been heard from inside the Westgate Mall this morning, where Kenyan Defence Forces are still involved in a hostage rescue operation.

Earlier the authorities said “most of the hostages” had already been rescued and the majority of the building had been secured in a major military operation.

The UK has offered Kenya assistance, including intelligence co-operation, in response to the attack by Islamic extremists in the upmarket shopping centre which has left 68 dead and more than 170 injured, including many children.

One of the Britons killed in the attack has been named in reports as Ross Langdon, who had dual nationality with Australia.

The architect is believed to have died alongside his girlfriend who was heavily pregnant.